Nanopillar Arrays with Superior Mechanical Strength and Optimal Spacing for High Sensitivity Biosensors

Recently, many types of vertically aligned slender nanostructures, such as nanotubes and nanorods have been fabricated for use in biosensors development because of their increased surface area. Lately, evidence has emerged to reveal that these nanostructures could not sustain the interaction forces exerted on them in an aqueous environment. Upon water contact, these nanostructures deformed severely, thus posing a serious problem for use in functional devices. To develop mechanically strong nanostructures, we used an aqueous based electrochemical deposition technique and developed vertically aligned nanopillar arrays. The mechanical strength of these structures was evaluated by exposing them to a water droplet and using them as working electrode in an electrochemical process. The nanopillar arrays were examined under SEM afterwards, and no deformation or bunching was observed. A higher faradaic redox peak was observed for the nanopillared electrode as compared with the flat electrode, which implies the increase in total flux at the nanopillar arrays is due to the sufficiently large spacing between these nanopillars. The nanopillar arrays fabricated in this study have sufficient mechanical strength to withstand the aqueous interaction forces. Furthermore, the rise in faradaic redox peak with nanopillar arrays suggests the possibility of using them for high sensitivity sensors.